1. Technical Field of the Invention
The present invention relates to communication systems and, more particularly, to an integrated local area communication system.
2. Description of Related Art
Recent advances in wireless telecommunications have been multi-faceted, resulting in a myriad of new products and services. In the mobile cellular telecommunications area, some of the new services include both private services usually provided within a home or business environment for private mobile subscribers and public services provided through a public land mobile network for public mobile subscribers. Both private and public mobile service may be provided on a cellular basis, with mobile subscribers being allowed to roam between the geographic coverage areas of different base stations of each of the private and public systems.
Private mobile service is typically provided through a private mobile telephony network that is implemented using a private cordless system standard such as the Cordless Telephone Standard 2 (CT-2). Private telephony systems may be provided as stand-alone networks or connected to a fixed telephony network.
Public mobile service is, on the other hand, generally provided through a cellular telecommunications network using one of the common cellular transmission standards such as the Advanced Mobile Phone Service (AMPS) System Standard, or the Global System for Mobile Communication (GSM) Standard.
Another direction in which there have been related developments is the area of cordless telephony products. Cordless telephone communications systems that are connected to a public switching telephone system (PSTN) have been known for some time. Cordless telephones operate utilizing a portable telephone unit in communication with a base station through a pair of radio frequency (RF) transceivers in the portable unit and in the base station. When the device is operable and a call is placed, dial tone and voice signals are transmitted from the RF transmitter in the portable unit to the RF receiver in the base station, and then over the PSTN lines in the ordinary manner. Similarly, when a call is received, the voice signals are transmitted from the RF transmitter in the base station to the RF receiver in the portable unit.
Although cordless telephones are convenient in that they allow telephone communication without the impaired-mobility imposed by a cord, they still require, like conventional corded telephones, usage of at least one hand to hold the portable unit for operating. Recent attempts that address the limitations of conventional cordless telephones have resulted in headset-like portable units that allow hands-free operation. In U.S. Pat. No. 4,882,745 to Silver, a "cordless headset telephone" is described in which only a single earphone is included to cover one ear while leaving the other ear open. Another related device is disclosed in U.S. Pat. No. 4,741,030 to Wilson, wherein a cordless headset is provided with a dial board positioned near the microphone for easy viewing by the user. As in the Silver device, the Wilson device does not disclose the use of two earphones and a volume control to enhance sound quality and to block external ambient noise. Another cordless telephone headset using only a single earphone is disclosed in U.S. Pat. No. 4,484,029 to Kennedy.
A recent improvement over these above-mentioned cordless telephone headsets is described in U.S. Pat. No. 5,113,428, wherein the portable unit is totally contained in a headset having its own push button key pad, related control buttons, a rechargeable battery, an RF transceiver and two earphones with volume control.
A co-assigned pending U.S. Patent Application, entitled "MODULAR UNIT HEADSET", cross-referenced hereinabove and incorporated by reference herein, describes an integrated system wherein a host electronic system, coupled to a PSTN, is capable of communicating with a headset by both wireless and wired means due to a modular unit attached to it. In yet another co-assigned pending U.S. Patent Application, entitled "ELECTRONIC EQUIPMENT AUDIO SYSTEM", cross-referenced hereinabove and incorporated by reference herein, describes a module port having a module connector, that is capable of communicating with a microphone via wireless and wired means.
Another application for the use of wireless headsets is in the Small Office/Home Office (SOHO) environment. This application could, for example, operate in the 2.4 GHz to 2.5 GHz frequency range. It would be advantageous to incorporate not only wireless headsets into a wireless network, but also facsimile machines, cordless telephones, and data terminals of various types. A problem associated with wireless communication is that of supplying power to portable devices. Since they are portable, the devices must rely on batteries and in order to extend battery life while at the same time keeping batteries small and light weight, every effort must be taken to conserve power consumption.
It is readily apparent that a logical progression of these multi-faceted advances is towards increased inter-operability and modularized integration of multiple physical devices so as to enhance human operator convenience. For example, it would be an advantage to have a mobile station equipped with a modular unit that is capable of communicating with a cordless phone base station so that it can operate as an extension of the cordless phone to effectuate land line communication. It would be of further advantage to have a wireless headset that is capable of communicating on a single protocol with both the mobile station and cordless phone base station. In such a system, the human operator has the benefit of hands-free operation of multiple telecommunications devices without having to interchange different modular units. Additionally, it can be readily appreciated that it would be of significant advantage to inter-operably integrate an electronic data terminal into such a local area communication system (LACS) whereby the utility of the terminal is further maximized. It is apparent that such an electronic data terminal can be a computer, which in turn may be stand-alone or in a Local Area Network, or a telefax, a pager, a printer, a calculator or a hand-held data organizer. Further, integrating a conventional phone answering machine that is operable to play back an out-going greeting or a recorded caller message and to record an in-coming message, into the LACS will undoubtedly enhance operator convenience and the use of the device. The method and apparatus of the present invention and various components thereof provide such advantages.